• 32kB x 8 bit static RAM expansion module for TI-74 BASICALC or TI-95 PR

    From Lorenz Born@21:1/5 to All on Thu Mar 5 19:53:42 2020
    XPost: comp.sys.ti

    Dear all,

    I had the unique opportunity to buy a pocket TI-95 PROCALC calculator
    together with a Math Statistics, a Chemical Engineering library module,
    a PC-324 printer and a PC interface for around $40 here in Switzerland.

    Now I'm considering how the internal memory of only 8kByte could be
    expanded with a RAM memory module (RAM cartridge) with 32 kByte. In my
    opinion, this should work, since a ROM expansion (ROM cartridge) with a
    memory size of 32 kByte was also available for the TI-95 PROCALC calculator.

    What do you think about that? Has anyone worked with such a RAM
    extension before? Probably built by yourself. Of course, I would have to develop it first. I imagine using a SAMSUNG KM62256CLG-7L (see https://app.ultralibrarian.com/details/Samsung/KM62256CLG-7L?uid=93ce5ab184e94c09)
    32k x 8 bit low power CMOS static RAM (70ns).

    Would anyone other than me be interested in such a 32 kByte RAM
    cartridge? Thanks in advance for any help or comments.

    Best regards,
    Lorenz
    --
    Lorenz Born
    lorenz<dot>born<at>gmail<dot>com
    The computer gets faster! --Moore--

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  • From Tom Lake@21:1/5 to Lorenz Born on Fri Mar 6 06:30:31 2020
    On Thursday, March 5, 2020 at 1:53:43 PM UTC-5, Lorenz Born wrote:
    Dear all,

    I had the unique opportunity to buy a pocket TI-95 PROCALC calculator together with a Math Statistics, a Chemical Engineering library module,
    a PC-324 printer and a PC interface for around $40 here in Switzerland.

    Now I'm considering how the internal memory of only 8kByte could be
    expanded with a RAM memory module (RAM cartridge) with 32 kByte. In my opinion, this should work, since a ROM expansion (ROM cartridge) with a memory size of 32 kByte was also available for the TI-95 PROCALC calculator.

    What do you think about that? Has anyone worked with such a RAM
    extension before? Probably built by yourself. Of course, I would have to develop it first. I imagine using a SAMSUNG KM62256CLG-7L (see https://app.ultralibrarian.com/details/Samsung/KM62256CLG-7L?uid=93ce5ab184e94c09)
    32k x 8 bit low power CMOS static RAM (70ns).

    Would anyone other than me be interested in such a 32 kByte RAM
    cartridge? Thanks in advance for any help or comments.

    Best regards,
    Lorenz
    --
    Lorenz Born
    lorenz<dot>born<at>gmail<dot>com
    The computer gets faster! --Moore--

    I had a rare TI 32K cartridge. It was directly usable on the TI-74 but to use all 32K on the 95, you needed to do some manipulation:

    To allow full access:
    (numbers are in Hex)

    Store 20 in BFFC
    Store 7F in BFF4

    Key-by-key method:

    1. Enter Hex Mode by pressing CONV, BAS (on function key), HEX (on function key)
    2. Enter System mode by pressing FUNC, SYS (on function key), YES (on function key)
    3.Type 2,0
    4. Press STB (on function key)
    5. Type 2nd, B (on HYP key), 2nd, F (on RCL key), 2nd, F (on RCL key), 2nd C (on INCR key)
    6. Type 7, 2nd F (on RCL key)
    7. Type 2nd B (on HYP key), 2nd F (on RCL key), 2nd F (on RCL key), 4

    Now when you do a CAT of the file space on the cartridge, it will show 32752 bytes free. You can remove the cartridge, insert other cartridges,
    even press reset or insert the 32K cart in another machine. The number of free bytes on that 32K cart will still be correct.
    The number of free bytes is stored on the cartridge.

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  • From Lorenz Born@21:1/5 to Tom Lake on Fri Mar 6 17:32:35 2020
    On 2020-03-06 15:30, Tom Lake wrote:
    On Thursday, March 5, 2020 at 1:53:43 PM UTC-5, Lorenz Born wrote:
    Dear all,

    I had the unique opportunity to buy a pocket TI-95 PROCALC calculator
    together with a Math Statistics, a Chemical Engineering library module,
    a PC-324 printer and a PC interface for around $40 here in Switzerland.

    Now I'm considering how the internal memory of only 8kByte could be
    expanded with a RAM memory module (RAM cartridge) with 32 kByte. In my
    opinion, this should work, since a ROM expansion (ROM cartridge) with a
    memory size of 32 kByte was also available for the TI-95 PROCALC calculator. >>
    What do you think about that? Has anyone worked with such a RAM
    extension before? Probably built by yourself. Of course, I would have to
    develop it first. I imagine using a SAMSUNG KM62256CLG-7L (see
    https://app.ultralibrarian.com/details/Samsung/KM62256CLG-7L?uid=93ce5ab184e94c09)
    32k x 8 bit low power CMOS static RAM (70ns).

    Would anyone other than me be interested in such a 32 kByte RAM
    cartridge? Thanks in advance for any help or comments.

    Best regards,
    Lorenz
    --
    Lorenz Born
    lorenz<dot>born<at>gmail<dot>com
    The computer gets faster! --Moore--

    I had a rare TI 32K cartridge. It was directly usable on the TI-74 but to use all 32K on the 95, you needed to do some manipulation:

    To allow full access:
    (numbers are in Hex)

    Store 20 in BFFC
    Store 7F in BFF4

    Key-by-key method:

    1. Enter Hex Mode by pressing CONV, BAS (on function key), HEX (on function key)
    2. Enter System mode by pressing FUNC, SYS (on function key), YES (on function key)
    3.Type 2,0
    4. Press STB (on function key)
    5. Type 2nd, B (on HYP key), 2nd, F (on RCL key), 2nd, F (on RCL key), 2nd C (on INCR key)
    6. Type 7, 2nd F (on RCL key)
    7. Type 2nd B (on HYP key), 2nd F (on RCL key), 2nd F (on RCL key), 4

    Now when you do a CAT of the file space on the cartridge, it will show 32752 bytes free. You can remove the cartridge, insert other cartridges,
    even press reset or insert the 32K cart in another machine. The number of free bytes on that 32K cart will still be correct.
    The number of free bytes is stored on the cartridge.

    Tom, thank you for the very detailed explanation! This is new and very interesting for me. What else is saved in the last 16 bytes of the
    cartridge port memory map? Do you possibly know more about this? And why
    the two values #20 in BFFC and #7F in BFF4? Can these two hexadecimal
    values be explained? At the moment I don't see any connection with the
    memory size of 32768 bytes.
    --
    Lorenz Born, Switzerland
    "The computer gets faster!" -- Gordon E. Moore

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Tom Lake@21:1/5 to Lorenz Born on Fri Mar 6 13:38:08 2020
    On Friday, March 6, 2020 at 11:32:37 AM UTC-5, Lorenz Born wrote:
    On 2020-03-06 15:30, Tom Lake wrote:
    On Thursday, March 5, 2020 at 1:53:43 PM UTC-5, Lorenz Born wrote:
    Dear all,

    I had the unique opportunity to buy a pocket TI-95 PROCALC calculator
    together with a Math Statistics, a Chemical Engineering library module,
    a PC-324 printer and a PC interface for around $40 here in Switzerland.

    Now I'm considering how the internal memory of only 8kByte could be
    expanded with a RAM memory module (RAM cartridge) with 32 kByte. In my
    opinion, this should work, since a ROM expansion (ROM cartridge) with a
    memory size of 32 kByte was also available for the TI-95 PROCALC calculator.

    What do you think about that? Has anyone worked with such a RAM
    extension before? Probably built by yourself. Of course, I would have to >> develop it first. I imagine using a SAMSUNG KM62256CLG-7L (see
    https://app.ultralibrarian.com/details/Samsung/KM62256CLG-7L?uid=93ce5ab184e94c09)
    32k x 8 bit low power CMOS static RAM (70ns).

    Would anyone other than me be interested in such a 32 kByte RAM
    cartridge? Thanks in advance for any help or comments.

    Best regards,
    Lorenz
    --
    Lorenz Born
    lorenz<dot>born<at>gmail<dot>com
    The computer gets faster! --Moore--

    I had a rare TI 32K cartridge. It was directly usable on the TI-74 but to use all 32K on the 95, you needed to do some manipulation:

    To allow full access:
    (numbers are in Hex)

    Store 20 in BFFC
    Store 7F in BFF4

    Key-by-key method:

    1. Enter Hex Mode by pressing CONV, BAS (on function key), HEX (on function key)
    2. Enter System mode by pressing FUNC, SYS (on function key), YES (on function key)
    3.Type 2,0
    4. Press STB (on function key)
    5. Type 2nd, B (on HYP key), 2nd, F (on RCL key), 2nd, F (on RCL key), 2nd C (on INCR key)
    6. Type 7, 2nd F (on RCL key)
    7. Type 2nd B (on HYP key), 2nd F (on RCL key), 2nd F (on RCL key), 4

    Now when you do a CAT of the file space on the cartridge, it will show 32752 bytes free. You can remove the cartridge, insert other cartridges,
    even press reset or insert the 32K cart in another machine. The number of free bytes on that 32K cart will still be correct.
    The number of free bytes is stored on the cartridge.

    Tom, thank you for the very detailed explanation! This is new and very interesting for me. What else is saved in the last 16 bytes of the
    cartridge port memory map? Do you possibly know more about this? And why
    the two values #20 in BFFC and #7F in BFF4? Can these two hexadecimal
    values be explained? At the moment I don't see any connection with the memory size of 32768 bytes.
    --
    Lorenz Born, Switzerland
    "The computer gets faster!" -- Gordon E. Moore

    7F20 hex is decimal 32544. That's the memory size of the 32K cartridge after some bytes (224 decimal bytes) are taken for housekeeping. Since this is an 8-bit machine, you have to enter the hex value in two parts - 20 which is the LSB (least significant
    byte) and 7F which is the MSB (most significant byte)

    I don't have any other information about data in the cartridge port. Sorry!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Lorenz Born@21:1/5 to Tom Lake on Sat Mar 7 11:03:34 2020
    On 2020-03-06 22:38, Tom Lake wrote:
    On Friday, March 6, 2020 at 11:32:37 AM UTC-5, Lorenz Born wrote:
    On 2020-03-06 15:30, Tom Lake wrote:
    ...
    Tom, thank you for the very detailed explanation! This is new and very
    interesting for me. What else is saved in the last 16 bytes of the
    cartridge port memory map? Do you possibly know more about this? And why
    the two values #20 in BFFC and #7F in BFF4? Can these two hexadecimal
    values be explained? At the moment I don't see any connection with the
    memory size of 32768 bytes.

    7F20 hex is decimal 32544. That's the memory size of the 32K cartridge after some bytes (224 decimal bytes) are taken for housekeeping. Since this is an 8-bit machine, you have to enter the hex value in two parts - 20 which is
    the LSB (least significant byte) and 7F which is the MSB (most significant byte)

    I don't have any other information about data in the cartridge port. Sorry!

    Tom, thanks again for your patience and answering my questions! In the meantime, my clarifications based on the TI-95 ROM listings (see http://www.rskey.org/CMS/index.php/the-library/13) have shown the
    following in the table below.

    xx = value not (yet) known
    specific hexadecimal value applies to a 32kB module (RAM cartridge)

    -------+-----+---------------------------------------------------- address|value|function, description or assumption -------+-----+----------------------------------------------------
    BFF0 | xx | unknown yet or no function -------+-----+----------------------------------------------------
    BFF1 | xx | unknown yet or no function -------+-----+----------------------------------------------------
    BFF2 | xx | probably MSB of used space (byte) in directory -------+-----+----------------------------------------------------
    BFF3 | xx | LSB of used space (byte) in directory -------+-----+----------------------------------------------------
    BFF4 | 7F | MSB of free bytes in cartridge (for 32kB) -------+-----+----------------------------------------------------
    BFF5 | FF | LSB of free bytes in cartridge (for 32kB) -------+-----+----------------------------------------------------
    BFF6 | xx | MSB of number of files (in cartridge) -------+-----+----------------------------------------------------
    BFF7 | xx | LSB of number of files (in cartridge) -------+-----+----------------------------------------------------
    BFF8 | 4E | character "N" \
    -------+-----+------------------ |
    BFF9 | 45 | character "E" > name of cartridge (?) -------+-----+------------------ |
    BFFA | 57 | character "W" / -------+-----+----------------------------------------------------
    BFFB | xx | info byte of cartridge -------+-----+----------------------------------------------------
    BFFC | 20 | cartridge memory size in kB (20h=32d) -------+-----+----------------------------------------------------
    BFFD | xx | MSB of entry address of cartridge -------+-----+----------------------------------------------------
    BFFE | xx | LSB of entry address of cartridge -------+-----+----------------------------------------------------
    BFFF | 6A | signature byte of cartridge -------+-----+----------------------------------------------------

    Knowledge gained by analyzing the files rom-cd1.asm and rom-cd3.asm. But
    not yet fully understood everything.

    Perhaps this is also of interest to you. I am now trying to use the
    TI-95 statistical library module to find out which values are available
    at the addresses above -- if any. Maybe new insights may arise here.

    BR Lorenz
    --
    Lorenz Born, Switzerland
    "The computer gets faster!" -- Gordon E. Moore

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  • From Tom Lake@21:1/5 to All on Sat Mar 7 06:04:15 2020
    On Saturday, March 7, 2020 at 5:03:35 AM UTC-5, Lorenz Born wrote:
    It looks like you don't need to reserve those 224 bytes after all. You'd just need to change these three locations by entering the byte in the second column:

    BFF4 | 7F | MSB of free bytes in cartridge (for 32kB) -------+-----+----------------------------------------------------
    BFF5 | FF | LSB of free bytes in cartridge (for 32kB)
    -------+-----+----------------------------------------------------
    BFFC | 20 | cartridge memory size in kB (20h=32d) -------+-----+----------------------------------------------------

    Thanks for the link!

    Tom L

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